<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>清楚元素默认的内外边距</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }

        div{
            margin: 300px  150px 30px 310px;
        }
    </style>
</head>
<body>
    111
    <h2>222</h2>
    <div>3333</div>
    <div>3333</div>
</body>
</html>